What a Sprint Burndown Chart Reflects in Agile & Scrum

Visualization is a key part of Agile projects. It supports transparency and collaboration and helps as an aid to visually measure progress and success. There are several tools available for visualization of agile projects and the most important among them, undoubtedly, is the burndown chart.

In this blog, we attempt to understand more about burndown charts and what the sprint burndown chart reflects in Agile projects.

What Is a Burndown Chart?

“A burndown chart shows the amount of work that has been completed in an epic or sprint, and the total work remaining. Burndown charts are used to predict your team's likelihood of completing their work in the time available. They're also great for keeping the team aware of any scope creep that occurs.”—Atlassian Agile Coach   

In other words, a burndown chart in Agile Scrum Methodology is a metric that helps to visually measure the amount of work completed in a day against the projected rate of completion for the existing sprint or release. Since it shows the daily progress, teams can gauge if they will be able to reach their milestones and deliver the required solution in the allocated time.

What Information Do Burndown Charts Convey?

Burndown charts give the following information in agile scrum projects: 

• Total estimate: This is the total effort in work hours that the team has committed to completing. This includes user stories or closing tickets or issues.  
• Amount of work left to be done: The burndown chart not only shows the amount of work completed but also the total work left to be done.  
• Total working days: This represents the total working days in a sprint or the sprint duration. This is necessary to be shown in the burndown chart as the team would need to calculate how much work is yet to be completed and how much time they can dedicate to the committed item.  
• Ideal effort: The ideal effort is a yardstick against which the team can measure its performance. It is represented by calculating the exact amount of effort remaining which needs to be burnt.  
• Actual effort: This is the total sum of all the remaining effort that is left at the end of each day. 

Reading a Burndown Chart in Agile Scrum

The burndown chart consists of  

• X Axis: Indicates time, usually in days 
• Y Axis: Indicates remaining work to be done in a sprint and can be represented by either number of tasks or remaining 
• Progress Line: Indicates the team progress through the sprint 
• Guideline: The projected estimate that is drawn downwards from top left to bottom right on the graph.  

The burndown char must be read by comparing the progress line with the guideline. The team can come to different conclusions based on how close the two lines are to each other. 

• If the progress line is above the guideline, it infers that the team is behind schedule.  
• If the two lines are very close together it means that they are on track and will achieve their target if they maintain this velocity. 
• If the progress line is below the guideline, it means that the team is well ahead of its schedule and may achieve targets even before the sprint ends.

How the Scrum Team Uses the Burndown Chart

The sprint starts with the Scrum team selecting the user stories that need to be completed in that sprint. The team refers to the product backlog and selects the tasks based on priority. The team then makes an estimation on when the task will be completed. The estimations are all added up to arrive at the cumulative amount which is called the effort remaining.

Effort remaining is then divided into the number of days that are still left in the sprint. Effort remaining is generally represented as story points on the Y-axis. By calculating the effort remaining, the team can zero in on how many hours have to be dedicated to a task.

How Burndown Charts Help in Agile Project Management

Burndown charts are a great tool for planning and visualising work as well as for allocating tasks. Let’s look at how it helps in these areas: 

• Planning: The burndown chart is a great planning and tracking tool and helps the Scrum Master and the Product Owner allocate tasks based on effort estimate. They can also identify if the project is on schedule or behind.  
• Scope Management: It helps teams understand if there has been a scope creep somewhere along the path of the sprint.  
• Schedule management: With a daily update of effort spent and effort remaining, the team can track if they are on schedule or not.  
• Risk analysis: With the daily feedback that it provides, a burndown chart helps to assess risks and catch and rectify them early on.  
• Communication: This is a great tool to communicate project and team progress to stakeholders and management. It is simple to understand and allows third parties to gauge the progress and productivity of the team.

How Does the Burndown Chart Look?

Let’s look at an example of a burndown chart: 

 In the above example, the X-axis represents the time while the story points have been represented on the Y-axis. From the graph the team is on track as depicted by the red line, which is very close to the projected estimate depicted by the blue line.   

Other Types of Burndown Charts

Let’s look at some other types of burndown charts: 

• Sprint Burndown Chart in Agile Scrum:

This is like the normal burndown charts; the difference being that it represents the work remaining in the sprint. This is shown on the X-axis, as the measurement of time in time units of a sprint or in other words the time duration of a sprint.  The sprint burndown chart has the following uses: 

• Helps to track team’s progress through the sprint 
• Helps track how much work is still left to do 
• Helps understand by when the goals can be met 

Let’s look at an example of a Sprint burndown chart:

This graph represents a sprint which is of one month duration. The red line shows the progress of the team as opposed to the estimated or predicted effort shown by the blue line. In this instance, the graph shows that the team is behind schedule and may not be able to complete the task within the projected date of July 1st.

• Release Burndown Chart:

This helps to track the team’s progress over the period of release. The X-axis represents the time duration over the release.

The release burndown chart helps teams to track how much time is remaining in the release and how fast the team is working through the product backlog. 

Let’s look at an example of a Release burndown chart

The red line represents the work being completed by the team and the blue line shows the ideal or projected timeline. The team represented in this graph is very close to the projected timeline and is likely to reach its target.  

1. Updating the release burndown chart: The release burndown chart is usually updated by the Scrum Master at the end of the sprint.  
2. While this is a great way to track the progress of the team through the sprint, it’s not the best alternative for projects that have constantly changing requirements.

• Burndown Bar Chart:

A burndown bar chart has bars. The height of the bars represents the amount of work remaining in the sprint or release. There are a few things to be considered when creating burndown bar charts: 

• The top is lowered every time any work is completed 
• The top is moved up or down each time work is re-estimated 
• The bottom is lowered when new work is added 
• The bottom is raised when work is removed

•  SAFe Agile Burndown Chart

The Scaled Agile Framework is a scaling framework that helps to scale Agile to the enterprise level. The SAFe burndown chart also called the PI burndown chart also represents the effort remaining over a period of time. By showing the progress that is being made towards the program increment timebox, this tool helps to track the work that has been planned for a PI against the work that has been accepted.

The horizontal X-axis in this chart shows the sprints while the vertical Y-axis shows the amount of work remaining at the start of each sprint.

The graph shows two lines. One is the planned line that is the sum of story points from all the teams and sprints and the other is the actual line that is the total of ‘done’ story points by all the teams.

• Burn Up Chart 

Like the burndown chart, a burnup chart is also used to track the progress of the project. But unlike the burndown chart, the burnup chart shows how much work has been completed and the total amount of work. The burnup chart also shows information like work done in the previous increments and scope creep.

The X axis on the burnup chart represents the time and the Y axis represents the story points or any other unit of work. 

Here’s an example of a Burnup chart:

This graph above represents a typical burnup chart. The red line shows the work that has been completed and the blue line shows the ideal line. This graph shows that the team was behind schedule but ultimately reached the target by removing some work from the sprint. 

• Release Burnup Chart 

Similar to the release burndown chart, the release burnup chart shows the work completed in the release till now. The X axis represents the dates until the release and the Y axis shows the amount of work, which could be story points or any other unit. The release burnup chart is a great visual tool to check if the release scope will be achieved.

Here's an example of a Release Burnup chart:

The red line represents the team’s progress while the blue line is the ideal or trend line. The red line is tapering down and shows that the team is unable to meet the deadline.

• Iteration Burndown Chart

The iteration burndown chart shows the work remaining in the iteration. It is a great tool to be used at the tie or retrospective meetings as the team can identify bottlenecks and pain points that may have caused problems during the iteration and try to fix them for the next iteration.

What Is Velocity in Agile?

At the end of each iteration, the team adds up effort estimates associated with user stories that were completed during that iteration. This total is called velocity—Agile Alliance   

Velocity helps the team to estimate how long it would take to complete the project. It’s a metric that provides a relative estimate and may not be a 100% accurate, but is a useful tool to identify how much work is yet to be done to complete the project and how long it will take for the team to move through the backlog and assign tasks effectively.

Agile Velocity Formula

Velocity is calculated by using the estimates on the remaining user stories and with the assumption that velocity will remain the same over the coming iterations. 

Velocity can be measured at different levels: 

• At the individual task level 
• At the team level 
• At the sprint level 
• At the epic or release level

Velocity of the team is calculated as:

Velocity of the team in Scrum = Number of total story points completed / number of sprints  

Sprint Velocity Chart

Understanding how much value your team can deliver in a sprint is a useful metric as it allows you to gauge productivity and figure out how much work can be accomplished by the team in future sprints. The Sprint velocity chart helps the product manager to do exactly that by showing the amount of value delivered by the team in each sprint.

Wrapping Up 

There are several types of burndown charts available and they are all geared towards helping teams and managers understand how much work is completed, and estimate when the work allocated will be accomplished. Most burndown charts are fairly easy to understand and are a great tool for communicating team productivity and project status.